The present invention relates to a charged particle beam apparatus and an image generation method.
As related technologies pertinent to a pulse counting system, there are techniques described in JP-A-2011-175811 and JP-A-4-332447.
JP-A-2011-175811 describes “a charged particle beam apparatus including: a determining section that determines whether an output signal corresponds to an output signal in a state in which a single charged particle enters the detector, or corresponds to an output signal in a state in which plural charged particles enter the detector; and a calculating section that generates an image by signal processing using the pulse counting system if it is determined that the output signal corresponds to an output signal in a state in which a single charged particle enters the detector, or generates an image by analogue signal processing if it is determined that the output signal corresponds to an output signal in a state in which plural charged particles enter the detector.”
JP-A-4-332447 describes that “if the pulse-counting electron detector is used in a scanning electron microscope or the like, it is configured to flexibly adjust contrast and brightness of an image. Subsequent to a pulse number counter 7, there are provided a multiplier 14 multiplying a counted value by any value and an adder 15 adding or subtracting any value to or from the counted value, or an input-output converting circuit having equivalent functions, and image data is generated using an output therefrom. This multiplier factor is controlled to be a value inversely proportional to a scanning speed, that is, time corresponding to a single pixel, and also set to be variable by using contrast and brightness adjusting means. It is possible to solve a problem particular to the pulse-counting system, that is, variation in data value depending on the scanning speed, thereby observing an image always having appropriate contrast in real time.”